MyBatis-plus：IPage分页

1、引入MyBatis-plus依赖

        
        
            com.baomidou
            mybatis-plus-extension
            3.4.2
            compile
        

2、创建配置类MybatisPlusConfig实现分页拦截

package com.heima.wemedia.config;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MybatisPlusConfig {


    /**
     * IPage的分页使用的是拦截器，属于物理分页，好处就是处理大量数据时，查询速度快。
     * @return
     */
    @Bean
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        //向Mybatis过滤器链中添加分页拦截器
        interceptor.addInnerInterceptor(new
                PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }

}

 3、业务代码

package com.heima.wemedia.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.heima.model.common.dtos.PageResponseResult;
import com.heima.model.common.dtos.ResponseResult;
import com.heima.model.common.wemedia.model.dto.WmMaterialDto;
import com.heima.model.common.wemedia.model.po.WmMaterial;
import com.heima.utils.thread.WmThreadLocalUtil;
import com.heima.wemedia.mapper.WmMaterialMapper;
import com.heima.wemedia.service.WmMaterialService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

/**
 * 

 * 自媒体图文素材信息表 服务实现类
 * 
 *
 * @author itcast
 * @since 2023-08-05
 */
@Service
@Slf4j
public class WmMaterialServiceImpl extends ServiceImpl implements WmMaterialService {

    /*获取素材列表*/
    @Override
    public ResponseResult list(WmMaterialDto dto) {

        //检查参数
        dto.checkParam();

        //构造分页查询
        IPage pageInfo = new Page(dto.getPage(),dto.getSize());//分页参数
        //条件查询器
        LambdaQueryWrapper lwq = new LambdaQueryWrapper<>();
        //判断是否收藏
        if(dto.getIsCollection() != null && dto.getIsCollection() == '1'){
            lwq.eq(WmMaterial::getCollection,dto.getIsCollection());
        }
        //按用户查询
        lwq.eq(WmMaterial::getUserId,WmThreadLocalUtil.getUser().getId());
        //按时间排序
        lwq.orderByDesc(WmMaterial::getCreatedTime);

        //执行iservice的page查询
        pageInfo = page(pageInfo,lwq);

        //结果返回
        ResponseResult responseResult =
                new PageResponseResult(
                        dto.getPage(),
                        dto.getSize(),
                        (int)pageInfo.getTotal());

        responseResult.setData(pageInfo.getRecords());
        return responseResult;
    }
}